JSON文件递归迭代返回“ undefined”和找到的值

Question

I'm trying to iterate through a json file to build a folder and file structure from a template. However when I specify a specific key to log it logs both the keys, AND the values I want. Is there any way to fix this issue? Why is it even doing this?

 function scan(obj) { if (obj instanceof Object) { for (var k in obj) { if (obj.hasOwnProperty(k)) { scan(obj[k]); var val = obj[k]; console.log(val.dir + '/' + val.file+ '.'+val.ext + '\\n'); } } } } json = [ { "dir": ".github", "nodes": [ { "file": "ISSUE_TEMPLATE", "ext": "md", "data": true } ] }, { "dir": ".vscode", "nodes": [ { "file": "extensions", "ext": "json" }, { "file": "settings", "ext": "json" } ] }, { "dir": "app", "nodes": [ { "dir": "src", "nodes": [ { "dir": "crash", "nodes": [ { "dir": "styles", "nodes": [ { "file": "crash", "ext": "scss" } ] }, { "file": "index", "ext": "tsx" } ] }, { "dir": "lib" }, { "dir": "main-process", "nodes": [ { "dir": "menu", "nodes": [ { "file": "index", "ext": "ts" } ] }, { "file": "main", "ext": "ts" } ] }, { "dir": "models" }, { "dir": "shared-process", "nodes": [ { "file": "index", "ext": "ts" } ] }, { "dir": "ui", "nodes": [ { "file": "index", "ext": "tsx" } ] } ] }, { "dir": "static", "nodes": [ { "dir": "common" }, { "dir": "logos" }, { "file": "error", "ext": "html", "data": true }, { "file": "index", "ext": "html", "data": true } ] }, { "dir": "styles", "nodes": [ { "dir": "mixins" }, { "dir": "ui", "nodes": [ { "file": "_app-menu-bar", "ext": "scss" }, { "file": "_focus", "ext": "scss" }, { "file": "_title-bar", "ext": "scss" } ] }, { "file": "_globals", "ext": "scss" }, { "file": "_mixins", "ext": "scss" }, { "file": "_type", "ext": "scss" }, { "file": "_ui", "ext": "scss" }, { "file": "_variables", "ext": "scss" }, { "file": "_vendor", "ext": "scss" }, { "file": "appname", "ext": "scss" } ] }, { "dir": "test" }, { "file": "package", "ext": "json", "data": true }, { "file": "webpack.common", "ext": "js" }, { "file": "webpack.development", "ext": "js" }, { "file": "webpack.production", "ext": "js" } ] }, { "dir": "docs", "nodes": [ { "dir": "contributing", "nodes": [ { "file": "setup", "ext": "md" }, { "file": "styleguide", "ext": "md" }, { "file": "tooling", "ext": "md" }, { "file": "troubleshooting", "ext": "md" } ] }, { "dir": "process", "nodes": [ { "file": "issue-triage", "ext": "md" }, { "file": "releasing-updates", "ext": "md" }, { "file": "reviews", "ext": "md" }, { "file": "roadmap", "ext": "md" } ] }, { "dir": "technical" }, { "file": "installation", "ext": "md" }, { "file": "README", "ext": "md" } ] }, { "dir": "script", "nodes": [ { "file": "build" }, { "file": "debug" }, { "file": "dist-info", "ext": "js" }, { "file": "package" }, { "file": "publish" }, { "file": "run", "ext": "js" }, { "file": "start" } ] }, { "file": ".gitmodules" }, { "file": ".travis", "ext": "yml" }, { "file": "appveyor", "ext": "yml" } ] scan(json) 

Answer 1

You need to specify the parent directory in your recursive function otherwise the parent dir will always be null. Also you should pass only your nodes array to the next call rather than the whole subdocument :

 function scan(parent, obj) { for (var k in obj) { if (obj[k]) { if (obj[k].nodes && obj[k].dir) { scan(parent + '/' + obj[k].dir, obj[k].nodes); } if (obj[k].file && obj[k].ext) { console.log(parent + '/' + obj[k].file + '.' + obj[k].ext + '\\n'); } } } } json = [{ "dir": ".github", "nodes": [{ "file": "ISSUE_TEMPLATE", "ext": "md", "data": true }] }, { "dir": ".vscode", "nodes": [{ "file": "extensions", "ext": "json" }, { "file": "settings", "ext": "json" } ] }, { "dir": "app", "nodes": [{ "dir": "src", "nodes": [{ "dir": "crash", "nodes": [{ "dir": "styles", "nodes": [{ "file": "crash", "ext": "scss" }] }, { "file": "index", "ext": "tsx" } ] }, { "dir": "lib" }, { "dir": "main-process", "nodes": [{ "dir": "menu", "nodes": [{ "file": "index", "ext": "ts" }] }, { "file": "main", "ext": "ts" } ] }, { "dir": "models" }, { "dir": "shared-process", "nodes": [{ "file": "index", "ext": "ts" }] }, { "dir": "ui", "nodes": [{ "file": "index", "ext": "tsx" }] } ] }, { "dir": "static", "nodes": [{ "dir": "common" }, { "dir": "logos" }, { "file": "error", "ext": "html", "data": true }, { "file": "index", "ext": "html", "data": true } ] }, { "dir": "styles", "nodes": [{ "dir": "mixins" }, { "dir": "ui", "nodes": [{ "file": "_app-menu-bar", "ext": "scss" }, { "file": "_focus", "ext": "scss" }, { "file": "_title-bar", "ext": "scss" } ] }, { "file": "_globals", "ext": "scss" }, { "file": "_mixins", "ext": "scss" }, { "file": "_type", "ext": "scss" }, { "file": "_ui", "ext": "scss" }, { "file": "_variables", "ext": "scss" }, { "file": "_vendor", "ext": "scss" }, { "file": "appname", "ext": "scss" } ] }, { "dir": "test" }, { "file": "package", "ext": "json", "data": true }, { "file": "webpack.common", "ext": "js" }, { "file": "webpack.development", "ext": "js" }, { "file": "webpack.production", "ext": "js" } ] }, { "dir": "docs", "nodes": [{ "dir": "contributing", "nodes": [{ "file": "setup", "ext": "md" }, { "file": "styleguide", "ext": "md" }, { "file": "tooling", "ext": "md" }, { "file": "troubleshooting", "ext": "md" } ] }, { "dir": "process", "nodes": [{ "file": "issue-triage", "ext": "md" }, { "file": "releasing-updates", "ext": "md" }, { "file": "reviews", "ext": "md" }, { "file": "roadmap", "ext": "md" } ] }, { "dir": "technical" }, { "file": "installation", "ext": "md" }, { "file": "README", "ext": "md" } ] }, { "dir": "script", "nodes": [{ "file": "build" }, { "file": "debug" }, { "file": "dist-info", "ext": "js" }, { "file": "package" }, { "file": "publish" }, { "file": "run", "ext": "js" }, { "file": "start" } ] }, { "file": ".gitmodules" }, { "file": ".travis", "ext": "yml" }, { "file": "appveyor", "ext": "yml" } ] scan('', json)